JPS5920171B2 - Information reading device using laser beam - Google Patents
Information reading device using laser beamInfo
- Publication number
- JPS5920171B2 JPS5920171B2 JP51063945A JP6394576A JPS5920171B2 JP S5920171 B2 JPS5920171 B2 JP S5920171B2 JP 51063945 A JP51063945 A JP 51063945A JP 6394576 A JP6394576 A JP 6394576A JP S5920171 B2 JPS5920171 B2 JP S5920171B2
- Authority
- JP
- Japan
- Prior art keywords
- photoelectric conversion
- laser
- information
- light source
- conversion device
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 238000006243 chemical reaction Methods 0.000 claims description 22
- 238000010586 diagram Methods 0.000 description 3
- 230000010355 oscillation Effects 0.000 description 3
- 230000003321 amplification Effects 0.000 description 1
- 238000003199 nucleic acid amplification method Methods 0.000 description 1
Landscapes
- Optical Recording Or Reproduction (AREA)
- Optical Head (AREA)
- Television Signal Processing For Recording (AREA)
Description
【発明の詳細な説明】
本発明はレーザービームを情報媒体に照射するレーザー
光源と、情報媒体からの反射光を受光して情報信号を発
生する光電変換装置とを具えるレーザービームによる情
報読取装置に関するものである。Detailed Description of the Invention The present invention provides an information reading device using a laser beam, which includes a laser light source that irradiates an information medium with a laser beam, and a photoelectric conversion device that receives reflected light from the information medium and generates an information signal. It is related to.
第１図はこのような情報読取装置を示すもので、レーザ
ー光源１からのレーザー出力ビームをアイソレータ２を
経てレンズ３により情報媒体４上に集光させる。FIG. 1 shows such an information reading device, in which a laser output beam from a laser light source 1 passes through an isolator 2 and is focused onto an information medium 4 by a lens 3.
この情報媒体４は、例えば画像情報を記録したビデオデ
ィスクとすることができる。情報媒体４で反射されるレ
ーザービームを再びレンズ３を経てアイソレータ２に戻
し、ここで反射させた後光電変換素子５に入射させ、情
報媒体４での反射光量の変化に対応した情報信号を発生
させる。この情報信号を更に増幅器６で増幅し、出力端
子７に供給する。このような情報読取装置においては、
アイソレータ２が理想的に構成されていれば、反射光は
全て光電変換素子５に入射され、レーザー光源１に戻る
ことはないが、実際にはアイソレータ２は理想的なもの
ではなく、反射光の一部がレーザー光源１に戻る。This information medium 4 can be, for example, a video disc on which image information is recorded. The laser beam reflected by the information medium 4 is returned to the isolator 2 via the lens 3 again, and after being reflected there, it is made incident on the photoelectric conversion element 5 to generate an information signal corresponding to the change in the amount of light reflected by the information medium 4. let This information signal is further amplified by an amplifier 6 and supplied to an output terminal 7. In such an information reading device,
If the isolator 2 is ideally configured, all of the reflected light will be incident on the photoelectric conversion element 5 and will not return to the laser light source 1. However, in reality, the isolator 2 is not ideal and the reflected light is A portion returns to the laser light source 1.
この反射光量は情報に応じて変動するものであるから、
レーザー光源１の発振が不安定になり、発振出力光が変
動することになる。この出力レーザービームの変動は当
然情報信号の振幅の変動となり、雑音成分となる。レー
ザー出力ビームを安定化するためにレーザー出力ビーム
の一部を第２の光電変換装置で受光し、その出力電気信
号をレーザー電源へフィードバックしてレーザー出力ビ
ームの変動を抑止することは、例えば特開昭５１−２９
８２１号公報に記載されているように既知である。この
ようなフィードバック制御によれば温度変動、電源電圧
の変動、経時変化などの比較的ゆつくりとした変動に対
してはこれを有効に補償することができるが、情報媒体
からの情報により輝度変調された反射光がレーザー光源
へ入射してレーザー光源の発振が不安定となつて生ずる
雑音を有効に除去することは困難であり、情報信号中に
は依然として雑音が混入されることになる。本発明の目
的は、上述したレーザー出力ビームの変動に基因して情
報信号に混入される雑音を軽減し得るようにした情報読
取装置を提供せんとするものである。Since the amount of reflected light changes depending on the information,
The oscillation of the laser light source 1 becomes unstable, and the oscillation output light fluctuates. This fluctuation in the output laser beam naturally results in a fluctuation in the amplitude of the information signal, which becomes a noise component. In order to stabilize the laser output beam, a part of the laser output beam is received by a second photoelectric conversion device, and the output electric signal is fed back to the laser power source to suppress fluctuations in the laser output beam, for example. Kaisho 51-29
It is known as described in Japanese Patent No. 821. This type of feedback control can effectively compensate for relatively slow fluctuations such as temperature fluctuations, power supply voltage fluctuations, and changes over time; however, brightness modulation due to information from the information medium It is difficult to effectively remove the noise generated when the reflected light enters the laser light source and the oscillation of the laser light source becomes unstable, and the noise will still be mixed into the information signal. SUMMARY OF THE INVENTION An object of the present invention is to provide an information reading device capable of reducing noise mixed into an information signal due to the above-mentioned fluctuations in the laser output beam.
本発明は、レーザービームを情報媒体に照射するレーザ
ー光源と、その反射光を受光して情報信号を表わす電気
信号を発生する第１の光電変換装置と、前記レーザー光
源の出力ビームの一部を受光してレーザービームの変動
を表わす電気信号を発生する第２の光電変換装置と、こ
の第２光電変換装置からの出力電気信号と前記第１光電
変換装置からの出力電気信号とを相殺してレーザー出力
ビームの変動による雑音を軽減した情報信号を取り出す
ようにしたことを特徴とするものである。The present invention includes a laser light source that irradiates an information medium with a laser beam, a first photoelectric conversion device that receives the reflected light and generates an electrical signal representing an information signal, and a first photoelectric conversion device that generates an electric signal representing an information signal. a second photoelectric conversion device that receives light and generates an electrical signal representing a fluctuation in the laser beam; and a second photoelectric conversion device that cancels out an output electrical signal from the second photoelectric conversion device and an output electrical signal from the first photoelectric conversion device. This is characterized in that an information signal with reduced noise due to fluctuations in the laser output beam is extracted.
次に図面を参照して本発明を詳細に説明する。第２図は
本発明情報読取装置の一例の構成を示す線図である。本
例において第１図に示した部品と同じ部品には同一符号
を付けて示す。本例においてはレーザー光源１とアイソ
レータ２との間にビームスプリツタ８を配置し、レーザ
ー光源１からのレーザー出力ビームの一部をこのビーム
スプリツタ８で反射させ、第２の光電変換素子９に入射
させる。この第２光電変換素子９からはレーザー光源１
の出力ビームの変動分のみを表わす電気信号が発生され
る。一方ビームスプリツタ８を透過したレーザービーム
はアイソレータ２に入射し、更にレンズ３により情報媒
体４上に集光される。情報媒体４からの反射光はレンズ
３を通り、アイソレータ２で反射され、光電変換素子５
に入射し、光電変換された情報信号が出力される。本発
明においても反射光の一部はアイソータ２を通過し、更
にビームスプリツタ８を経てレーザー光源１に戻るため
、レーザー光源１の動作は不安定となり、レーザー出力
ビームは変動することになる。Next, the present invention will be explained in detail with reference to the drawings. FIG. 2 is a diagram showing the configuration of an example of the information reading device of the present invention. In this example, parts that are the same as those shown in FIG. 1 are designated by the same reference numerals. In this example, a beam splitter 8 is arranged between the laser light source 1 and the isolator 2, and a part of the laser output beam from the laser light source 1 is reflected by the beam splitter 8, and a part of the laser output beam from the laser light source 1 is reflected by the second photoelectric conversion element 9. Inject it into the From this second photoelectric conversion element 9, a laser light source 1
An electrical signal representative of only the variations in the output beam is generated. On the other hand, the laser beam transmitted through the beam splitter 8 enters the isolator 2 and is further focused onto the information medium 4 by the lens 3. The reflected light from the information medium 4 passes through the lens 3, is reflected by the isolator 2, and is transmitted to the photoelectric conversion element 5.
The photoelectrically converted information signal is output. Also in the present invention, a part of the reflected light passes through the isorter 2 and returns to the laser light source 1 via the beam splitter 8, so the operation of the laser light source 1 becomes unstable and the laser output beam fluctuates.
したがつて光電変換素子５から供給される情報信号中に
はこのレーザー出力ビームの変動に起因する雑音が混入
されていることになる。本発明においてはこの雑音を相
殺して軽減するために、第２光電変換素子９の出力電気
信号を増幅器１０で増幅し、極性反転器１１で極性を反
転した後変調信号として変調器１２に供給する。この変
調器１２には増幅器６からの情報信号をも供給する。変
調信号の振幅を、ビームスプリツタ８の分割比または増
幅器１０の増幅率を調整することにより変え、情報信号
中に含まれる雑音を変調信号と相殺除去するようにする
。このようにして出力端子７では雑音信号が除去若しく
は軽減された情報信号が得られることになる。Therefore, the information signal supplied from the photoelectric conversion element 5 contains noise due to fluctuations in the laser output beam. In the present invention, in order to cancel and reduce this noise, the output electrical signal of the second photoelectric conversion element 9 is amplified by the amplifier 10, and after its polarity is inverted by the polarity inverter 11, it is supplied to the modulator 12 as a modulation signal. do. This modulator 12 is also supplied with the information signal from the amplifier 6. The amplitude of the modulated signal is changed by adjusting the division ratio of the beam splitter 8 or the amplification factor of the amplifier 10, so that the noise contained in the information signal is canceled out by the modulated signal. In this way, an information signal from which the noise signal has been removed or reduced is obtained at the output terminal 7.
第１図は従来のレーザービームによる情報読取装置の構
成を示す線図、第２図は本発明のレーザービームによる
情報読取装置の一例の構成を示す線図である。
１・・・・・・レーザー光源、２・・・・・・アイソレ
ータ、３・・・・・・レンズ、４・・・・・・情報媒体
、５・・・・・・光電変換素子、６・・・・・・増幅器
、９・・・・・・第２光電変換素子、１０・・・・・・
増幅器、１１・・・・・・極性反転器、１２・・・・・
・変調器。FIG. 1 is a diagram showing the configuration of a conventional information reading device using a laser beam, and FIG. 2 is a diagram showing the configuration of an example of the information reading device using a laser beam according to the present invention. DESCRIPTION OF SYMBOLS 1... Laser light source, 2... Isolator, 3... Lens, 4... Information medium, 5... Photoelectric conversion element, 6 ......Amplifier, 9...Second photoelectric conversion element, 10...
Amplifier, 11...Polarity inverter, 12...
・Modulator.
Claims (1)
と、その反射光を受光して情報信号を表わす電気信号を
発生する第１の光電変換装置と、前記レーザー光源の出
力ビームの一部を受光してレーザービームの変動を表わ
す電気信号を発生する第２の光電変換装置と、この第２
光電変換装置からの出力電気信号と前記第１光電変換装
置からの出力電気信号とを相殺してレーザー出力ビーム
の変動による雑音を軽減した情報信号を取り出すように
したことを特徴とするレーザービームによる情報読取装
置。1. A laser light source that irradiates an information medium with a laser beam, a first photoelectric conversion device that receives the reflected light and generates an electrical signal representing an information signal, and a first photoelectric conversion device that receives a part of the output beam of the laser light source. a second photoelectric conversion device that generates an electrical signal representing variations in the laser beam;
By means of a laser beam, the output electric signal from the photoelectric conversion device and the output electric signal from the first photoelectric conversion device are offset to extract an information signal with reduced noise caused by fluctuations in the laser output beam. Information reading device.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP51063945A JPS5920171B2 (en) | 1976-06-01 | 1976-06-01 | Information reading device using laser beam |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP51063945A JPS5920171B2 (en) | 1976-06-01 | 1976-06-01 | Information reading device using laser beam |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS52146604A JPS52146604A (en) | 1977-12-06 |
| JPS5920171B2 true JPS5920171B2 (en) | 1984-05-11 |
Family
ID=13243982
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP51063945A Expired JPS5920171B2 (en) | 1976-06-01 | 1976-06-01 | Information reading device using laser beam |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5920171B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS56127276A (en) * | 1980-03-10 | 1981-10-05 | Omron Tateisi Electronics Co | Photoelectric switch |
-
1976
- 1976-06-01 JP JP51063945A patent/JPS5920171B2/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| JPS52146604A (en) | 1977-12-06 |
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